Evaluation of liquefaction potential using cone penetration tests results after soil improvement for silty sand

Dynamic consolidation method was used to improve loose reclaimed silty sand ground against liquefaction at Mailiao in Taiwan. Cone penetration tests (CPT) were conducted to confirm the effect of the improvement. The cone tests are very economical and speedy to evaluate the improvement. Where qc-values were below a required value set out as the improvement criterion, boreholes were sunk with standard penetration tests (SPT) and disturbed soil samples were obtained for laboratory soil tests. A correlation between qc, fs and N-value proposed by Robertson was used to estimate N-values from the cone test results of qc and fs. Liquefaction potential was then calculated from the N-values so established. This procedure allowed the authors to made quick and economical evaluation of the liquefaction potential using the cone test results.